Heli-coil 05CSB Spiral Point Sti Tap 5-40 Unc 2 Flute

Product Description

The HELI-COIL 05CSB is a spiral point STI tap designed to cut internal threads for Heli-Coil thread insert installation. It is ground to STI UNC specifications, which produce an oversized thread profile to accept a coiled wire insert that restores or reinforces a standard thread to its original dimensions. The tap features a plug chamfer for starting in through-holes and is manufactured from high-speed steel with a bright, uncoated finish. With 2 flutes and an H1 thread limit, this tap suits production and maintenance threading operations in steel, aluminum, and similar materials where a 5-40 UNC insert installation is required.

This tap is used in applications where a 5-40 UNC Heli-Coil thread insert must be installed, including repair of stripped or damaged threads in light fastener assemblies, electronics enclosures, instrument housings, and precision mechanical components. It is appropriate for both bench repair work and light production threading. The plug chamfer allows use in through-hole applications. This tool is installed by machinists and maintenance technicians working with hand taps or low-speed machine tapping in ferrous and non-ferrous base materials.

Key Features

• STI UNC thread form produces the oversized profile required for Heli-Coil wire insert installation
• Plug chamfer with 2 flutes for through-hole threading operations
• H1 thread limit for close tolerance control on cut thread dimensions
• High-speed steel construction provides durability across a range of workpiece materials
• Bright, uncoated finish suitable for use with cutting fluids and oils
• 3B class of fit for standard commercial thread tolerances

Compatibility

Designed for use in Heli-Coil STI thread insert installation applications requiring a 5-40 UNC tapped hole. Compatible with standard 5-40 UNC Heli-Coil inserts installed in through-hole configurations.

Installation Notes

This tap is installed by a machinist or maintenance technician using a tap wrench or low-speed tapping machine. Ensure the workpiece is securely clamped and the tap is started square to the bore before applying cutting pressure. Use a suitable cutting fluid or tapping oil to extend tool life and improve thread finish. Follow the Heli-Coil insert manufacturer drill size recommendations before tapping to achieve the correct pre-tap hole diameter for the insert size.